By connecting your iPhone/iPad to your laptop via USB you can use the camera on that device to show your work when using the Zoom application on your computer. (This is not usable when using the web browser version of Zoom.) This can be extremely useful for students or professors who need to show a physical object or work handwritten on paper.
At this point you should now be sharing the camera from your phone. (You can also use this if you want to share other info displayed on your phone.) When you are finished, click the 'Stop Share' button at the top of your Zoom window.